1. Field of the Invention
The invention relates to a method and a device for monitoring the state of vehicle chassis. The invention is suitable for use in rail vehicles but is not restricted to this.
2. Description of the Related Art
Maintenance costs of rail vehicles and especially of their chassis represent a considerable fraction of the operating costs. Since it has hitherto not generally been possible to assess the actual state of chassis components of rail vehicles affected by wear or subjected to ageing process in the built-in state, testing and maintenance measures are usually carried out at fixed intervals which are associated with at least partial dismantling of the chassis. The maintenance intervals are selected to be so short that any damage or deterioration in the state of a chassis element which occurs in the meantime, does not yet result in a critical state. This has the consequence that an appreciable proportion of the work is carried out prematurely or a considerable proportion of the relevant chassis elements are replaced although no deterioration in their state has occurred.
A number of methods and devices are known for monitoring individual chassis components of rail vehicles.
A number of known solutions relate to the presence of wheel tyres or flanges. Such systems do not yield any prediction on the slowly changing state of a component but assess the instantaneous safety of the chassis system.
A number of other known solutions are restricted to measuring the vibrations or impacts in the chassis which occur during operation and only take into account the violation of pre-defined limits when making the assessment, whether this be tolerable amplitudes or reference spectra. Here also only a “good”-“bad” discrimination is therefore made.
In some known solutions a sensor is attached to components which are considered to be particularly critical, which specifically monitors this chassis element. No correlation is therefore made between the measurements at various points of the chassis. No prediction of the remaining lifetime is deduced from the measurements.